Sheet metal shears



Feb; 24, 1959 J. slLLAK 2,874,465

v SHEET METQL sHEARs Filed 0G15. 4, 1957 INVENTOR. JOSH-7H 6MM/4 F/g. 5V BY W United Statesv Patr-it SHEET METAL SHEARS Joseph Sillak, Yonkers, N. Y.

Application October 4, 1957, Serial No. 688,220

2 Claims. (Cl. 30250) This invention relates to a sheet metal shears.

An object of the invention is to provide a sheet metal shears which will produce cut edges disposed in substantially right angular relation with the plane of the sheet material without appreciably distorting the edge portions thereof.

Sheet metal shears in general use have the tendency to cant the sheet metal with reference to the plane of the cutting blades whereby the faces of the cut edges are not disposed in right angular relation with the plane of the sheet material and the portions of the sheet material adjacent the cut edges are distorted or bent out of the plane thereof which necessitates the straightening of the edge portions thereof before the same can be used. In order to overcome this objection to sheet metal shears now in general use, the present invention provides a sheet metal shears which is constructed and arranged for retaining the sheet metal in right angular relation with the plane of the cutter blades during the severing of the sheet to thereby produce a cut edge which is disposed in right angular relation with the sheet and the portions of the sheet along the severed edges are not distorted out of the plane of the sheet.

Another object of the invention is to provide a sheet metal shears having spaced side plates provided with confronting cutting edges and a shearing member movable between said side plates for effecting a double cut in a sheet so as to remove a narrow strip of the material therefrom in severing the sheet. p

Another object of the invention is to provide means for bending the narrow strip out of the plane of the sheet being severed and for cutting o the narrow strip from thesheet. 1

` Another object of the invention is to widen the space between the side plates below the cutting edges thereof so'asfto permit of the free movement of the narrow strip therebetween.` p Another object` of the invention is to provide cam means connecting the movable shearing member with a hand member for moving the saids'hearing'member between the side plates.

Still another object of the invention is to arrange said cam means for increasing the leverage action of the movable shearing member as the outer end thereof approaches the cutting edges of the side plates.

Still another object of the invention is to provide a sheet metal shears adapted for cutting any desired con- ,figuration of opening in sheet metal. i

With the foregoing and other objects in view, reference is'now made to the following specification and accompanying drawings in which the preferred embodiment :of the invention is illustrated.

vIn the drawings: Y f Fig. 1 is a side view of a sheet metal shears constructed in accordance with the invention.

Fig. 2 is a similar view with one of the side plates removed. i. i

Fig. 3 is a side view with one of the side plates removed and showing the movable cutter blade in open relation.

Fig. 4 is a sectional view taken approximately on line 4--4 of Fig. 3.

Fig. 5 is a sectional view taken approximately on line 5-5 of Fig. 1 with the cutter blade shown in open relation.

Fig. 6 is a sectional view taken approximately on line 6-6 of Fig. 3.

Referring to the drawings, the shears includes spaced side plates 10 and 11 which are formed with confronting cutting edges 12 and 13 extending along the curved peripheral edge portions 14 and 15 thereof respectively. The cutting edges 12 and 13 are formed by the intersection of the peripheral edgeportions 14 and 15 with the confronting face portions 16 and 17 of the side plates respectively. The peripheral edge portions 14 and 15 are beveled toward the outer faces thereof so as to produce sharp cutting edges 12 and 13.

Cooperating with the cutting edges 12 and 13 for shearing sheet metal and the like is a cutter blade 18 pivoted between the side plates on a pivot pin 19 and having oppositely disposed cutting edges 20 and 21 for producing a double shearing action to thereby cut out a narrow strip of the metal between the severed portions of the sheet. The cutting edges 20 and 21 are formed by the intersection of the opposite side faces 22 and 23 of said cutter blade with the straight edge portion 24 thereof. The cutter blade tapers in thickness toward the outer edge thereof whereby the outer portion of the cutter blade is thinner than the width cut out of the sheet metal in cutting the narrow strip. This permits of the convenient insertion of the cutter blade in the opening in the sheet metal formed by cutting out the narrow strip therefrom.

Rigidly aflixed to the side plates is a handle member 25 which,'as illustrated, has its inner end extending inwardly between the side plates and secured thereto by bolts 26. This disposes the side plates in spaced apart mating relation at their rear ends, the forward ends thereof being correspondingly spaced apart by means of a spacer element 27 secured therebetween by any desired means such' as `by a bolt 28 extending through the side plates and the spacer element and which secures the side plates together in mating spaced relation at their forward ends.

The cutter blade 18 is moved to effect a shearing action by means of a movable handle member 29 which is pivoted at its inner end 30 between the side plates on a pivot pin 31. The inner end 30 is formed with an arcuate periphery 32 having a point 33 as its center and with the pivot pin 31 offset in eccentric relation forwardly of the center 33 and to one side of a longitudinal medial line through the handle 29. The arcuate periphery 32 constitutes a cam which is disposed in engagement with a peripheral edge 34 of an arcuate recess provided in the inner end of the cutter blade 18.' The peripheral edge 34 includes a semi-circular edge portion 3S and substantially straight opposite edge portions 36 and 37 which are formed as continuations of the semicircular edge portion 35.

The semi-circular edge portion 35 is concentric with the inner end portion 30 of the handle 29 when the cutter blade is in closed relation as shown in Fig. 2 of the drawings. When the cutter blade is in open relation', the inner end portion 30 of the handle member 29 is n moved out of concentric Vrelation with the semi-circular ,shown in Fig. 3 of the drawings.

edge portion ,p35 and into spaced relation therewith as In this position the inner end portion 30 is in engagement with the straight ,outer edge portions 36 and 37. As the cutter blade 18 approaches closed'relation with the side plates 10 and 11,

Patented Feb. 24, 1959 the handle member approaches parallel relation with the handle member 25 with a consequent swinging movement of the inner end 30 into closer relation with the semieiredlar edge Portion .3.5.- The Swinging of the handle member 29'about its pivotal connection 31'ei`fects a eenling of the en tter blade L8 to Prodhee a .shearing action between the cutting edges 20 and Zl'thereof with the cutting edges 14 and 15 `of the side plates. The leverage aetion imparted to the entrer blade '1 8 by the handle member 29 progressively increases with the movement of the cutter blade toward closed relation.

Thus, arcuate periphery 32 of inner end 30' of the handle member is eorrlprieed in etleet by oppositely diS- noeed arenate earn edge portions whieh vSpiral outwardly in .opposite peripheral direetione relative to the Pivotal atisioi the handle member, Each `ol these eem portions has point .eontaet with one of opposite edge perdons 3 6 and 37 during .shear opening or lclosing movement. During shear closing movement, the point of contact with edge portion 3,6 moves counterclockwise about periphery 32 closer and closer to the airis of pin 31 while the point of contact with edge portion 37 also moves counterclockwise about perphery32 but farther and farther from the axis of pin 31. During shear opening movement, the paths of these points of contactare the same but the directions of movement along those paths are reversed. In this way, during movement of the handle in one direction, 4one portion of periphery 32 advances to serve as an actuating cam while the other portion of periphery 32 retreats to serve as a ca m follower guide to avoid play between the yhandle and the cutter blade; and during movement of the handle in the opposite direction lthe functions of the peripheral portions are reversed.

From a consideration of Figures 2 and 3, it will also b e no td that during shear opening movement the axes of pins 19 *and 31 and central point 33 are moving toward alignment with each other while during shear closing Vmovement they are moving away from alignment with each other. Moreover, it will also be clear from a comparison of vFigures 2 and 3 that the inner end of the handle is disposed deeper in the recess of the `cutting blade in e Closed Shear Position than in an oren shear position, and that movement o f these parts Atoward or away Vfromfeach other is progressive during movement of handle member 29. i

A particular feature of the invention is the severing of the narrow Strip from the Sheet of material being .eilt- Thieis elfeeted hy providing the `spacer elementv 27 with a laterally extending narrow cutting edge 38 llocated ,between the side platee l arid 11 at the forward end thereof- The elltreme end .of the cutter blade 1S iS torrned `with a laterally extending cutting edge 3.9 which cooperates with the cutting edge l3 8 fors'evering the narrow strip therebetween whenever the cutter blade 18 is moved to closed relation with the side 'plateev Thos. short ents may he madey in Sheet metal hy .the forward end portions of the cutter blade and side plates and the ynarrow strip severed or eut from the sheet in short lengths whieh will fall from between. the Side plates The entter .blade is fonned with a eurvededge portion 40 eX- tending laterally of the side plates to thereby curl the narrow strip away from the'cutting edges 12 and 13 `thereof and toward the remote side edges thereof when long cuts are made in the sheet metal,

The confronting ,Sidelfaeee ilalld .42 of the Side PlateS are recessed from the, narrow face portions 16 and 17 .to theremote sideedges thereof and between the spacer element y27 and a curved vline A3. Thiswidens the spacing .between the side plates throughout the recesses and provides a ,clearance Vfor the free Apassage of the narrow Strip .as it is formed in the shearing .operation- I'n order that the cottingedg'e 348 he properly Slldeed from the cut edge 3 Y9of the cutter blade '18, the spacer element 271s @sont ol de bolt 2a and is .idonea to be disposed in s et adjusted position by tightening of the bolt. The spacer element is formed with a narrow tongue 44 which projects from between the side plates for manually turning the spacer element to dispose the cutting edge 38 in the desired relation with the cutting edge 39.

Constructed in this manner the shears will cut thick guage sheet metal and the like without undue pressure applied to the handle member 29. The cut edges of the sheet produced by the cutting operation will be in substantially right angular relation with the plane of the sheet without substantially distorting the edge portions thereof. It will be understood that the distance between the pivots 19 and 31 provide aleverage which less'ens the pressure required to be applied to the handle 29 for moving the cutter blade 18 for cutting through sheet metal. The leveragealso provides greater cutting force in the cutter blade 18.

While thepreferred form o f the invention has been shown and described herein, it is to be understood that the same is not so limited but shall cover and include any and all modifications of the invention which fall within the purview thereof.

What is claimed is:

1. In a sheet metal shears, oppositely disposed side plates arranged inr spaced relation'and having confronting cutting edges extending longitudinally thereof, a handle member rigidly aflixed'to said side plates to extend outwardly thereof at one end, a cutter blade pivotally mounted between said side plates and having oppositely diSPosed cutting edges adapted to cooperate with the cutting edges o f the'side plates respectively for effecting sidebyfside cuts with the movement of the cutter blade, a handle n renlher having a Vforward end formed with oppositely disposed arcuate cam edge portions, said cutter blade having a recess including oppositely disposed outwardly extending edge portions,- said handle member being pivoted between said side plates in s aid recess in forwardly and laterally olrset relation from the Center of said arcuate cam edge portions and with both said cam edge portions of said handle member spiraling outwardly in opposite peripheral directions and having point Acontact with the .opposite edge Portions of Said reeese in an open shear'position and Vin a closed shear position', the

Point of eontaet of one earn edge of the handle with one said edge portion Yof the recess being nearer the'pivotal axis of the handle in said open shear position than in said closed shear position, the point of contact of the lotherleanr edge ogf lthe handle with the other Said edge .Portion of the receso being farther from the Pivotal allie of the handle in said open shear position than'in said eloeed Shear Position. the pivotal aires oi the editer blade and ,the handle and the eenter of Said arehate earn edge portions moving toward alignment with eaeh other ddring shear opening movement and away from alignrnent Vwith eaeh other during Shear `Closing movement, and ,Said forward end of the handle h roving ont of ,the ,reeeoe der ing Shear opening movement and into the reee'es daring shear closing movement.

2- ,in a Sheet I netal shears, oppositely disposed Side plates arranged in spaced relationahd having'eonfronting edtting edges` extending longitudinally thereof, a handle member rigidly affixed to said side'tplates to extendoutwardly thereof at one end, a cutter blade pivotally indented between Said side plateS and having oppositely disposed Cutting edges adapted to eooperate'with the putting edges of theside plates respectively for etfecting side-hyside elite .with the movement ofthe editer blade ,and having an .enter end ehtting edge extending between Said oppositely disposed edttin'g edges. a handle member adapted to move the cutter blaadeebetween open ,and dosed positions, a spaeernielnher mohntedlbetween the ende of'eaid ride Platesoppoeite the handle member tori rotation about ,an axisperpendiehlar to .the Side plates,"the spacer member having a cutting edge transverse to the cutting` edges of the side plates and adapted to cooperate with said outer end cutting edge of the cutter blade to complete the cut through a sheet of metal in one position of rotation of the spacer member, and means for selectively locking the spacer member in any of a plurality of positions of rotation relative to the side plates.

References Cited in the le of this patent UNITED STATES PATENTS 156,775 Dawson 7..- Nov. 10, 18'74 

